1. Field of the Invention
This invention relates generally to surgical forceps and scissors, and in particular, to a combination bipolar forceps and scissors surgical instrument.
2. Description of the Background Art
The utility of a surgical implement for performing both tissue cutting and coagulation has been identified and addressed previously by a number of designs. U.S. Pat. Nos. 4,655,216, 5,445,638, 5,458,598, and 5,573,535 all describe bipolar coagulating instruments with separately actuable single-blade cutting mechanisms. The single cutting blades featured in these designs lack precision due to the tendency of the blade to displace tissue from the grasper jaws while cutting tissue. Further, these designs expose sharpened portions of the cutting blade to tissue outside the grasper jaws, which creates the risk of inadvertent cutting of tissue and structures surrounding the intended treatment sight. Durability and longevity of the cutting blade can also be an issue with this cutting mechanism since it relies greatly on the sharpness of the delicate cutting edge. Further, the single-blade cutting mechanism suffers when compared to a conventional surgical scissors in terms of functionality.
Previous attempts at constructing combination bipolar forceps and scissors devices involved either segmenting the grasper jaws into a distal grasping and coagulating portion and a proximal shearing scissors portion, or employing two independent mechanisms for the graspers and scissors. The former approach, which is described in U.S. Pat. Nos. 5,342,381, 5,462,546, and 6,206,877 results in a device with relatively small grasping and coagulating surfaces and scissors mechanisms. This limits the area and thickness of tissue that can be coagulated and/or transected by the device. Further, because the scissor blades are fixed in place, it is possible to unintentionally cut tissue that has not been coagulated if great care is not taken when grasping tissue with the distal forceps portion of the jaw.
Designs featuring independent grasping and scissor mechanisms as described in U.S. Pat. No. 5,964,758 are mechanically complex. The scissor mechanisms are either permanently installed, which limits their utility as an a traumatic grasper or coagulating forceps, or controlled by a separate mechanism that further complicates their application.
Further, no forceps and scissor combinations previously described takes advantage of an offset electrode arrangement which greatly reduces the area of tissue coagulated during application of bipolar energy, and results in significantly reduced levels of undesirable collateral tissue damage. In conventional prior-art bipolar forceps, current 6 from the electrosurgical generator is passed between jaws 4 and 5 through tissue 7 captured between the jaws, as shown in FIGS. 1a and 1b. The arrangement of the electrodes in this opposing fashion causes some of the electrosurgical current 8 flowing between the jaws to pass through tissue outside of the jaws, thus causing collateral tissue destruction. Offset electrode technology is disclosed in U.S. Pat. No. 5,403,312, which is incorporated herein by reference.
U.S. Pat. No. 5,984,938 describes a forcep concept with deployable scissor inserts; however, this design describes a conventional mechanical grasper with sprung jaws, not a bipolar coagulating forcep with a hinged jaw. Further, the inserts described do not possess a sharpened leading edge, which would allow them to be used as tissue transectors.
Finally, the straight and un-tapered form of the jaws described in all of the previous disclosures limits user visibility of the distal tip, compromises their ability to access recessed structures, and prevents them from effectively being used as a mechanical dissector.
Thus, there is a need for an improved combination bipolar forceps and scissor device that overcomes deficiencies of prior art devices.
A surgical instrument is provided including a shaft having a proximal end and a distal end, a handpiece disposed at the proximal end of the shaft, and a grasping device disposed at the distal end of the shaft, and having a first jaw element and a second jaw element pivotally coupled to the first jaw element and selectively pivotable relative to the first jaw element between an open position and a closed position. The instrument also includes a cutting device having a first cutting element and a second cutting element pivotally coupled to the first cutting element. The cutting device is movable between a retracted position wherein it is positioned within the shaft and a extended position wherein it is disposed at the distal end of the shaft. When the cutting device is in the extended position, the first and second cutting elements are coupled to the first and second jaw elements respectively for movement therewith between open and closed positions.
In one embodiment the instrument further includes a grasper activation assembly for selectively moving the grasping device between the open and closed positions, and a cutting device activation assembly for selectively moving the cutting device between the retracted and extended positions. In yet another embodiment, the grasping activation assembly further includes a grasping activator element associated with the handpiece, and grasping activation coupling elements for coupling the grasping activator element with the grasping device so that selective movement of the grasping device between the open and closed positions can be accomplished by manipulating the grasping activator element. The cutting activation assembly also further comprises a cutting activator element associated with the handpiece, and cutting activator coupling elements for coupling the cutting activation element with the cutting device so that selective movement of the cutting device between the retracted and extended positions can be accomplished by manipulating the cutting activator element. In yet another embodiment, the grasping activation coupling elements include an elongate element positioned within the shaft, wherein longitudinal movement of the elongate element along the axis of the shaft causes the second jaw element to pivot relative to the first jaw element between the open and closed positions. Further, the cutting activation elements include an elongate element positioned within the shaft, wherein longitudinal movement of the elongate element along the axis of the shaft causes the cutting device to move between the retracted and extended positions.
In alternate embodiments, the instrument further includes at least one pair of bipolar electrodes contained within the first and second jaw elements respectively, the arrangement being such that when the grasping device is in the closed position, the electrodes are substantially facing towards one another and either substantially offset from one another or substantially opposing one another.
In yet another embodiment, the first and second jaw elements have first and second channels therein respectively. When in the extended position, the first and second cutting elements are positioned within the first and second channels respectively. In yet another embodiment, the instrument further includes means for impeding rotation of the grasping element when in the closed position. In an alternate embodiment, the first and second cutting elements have first and second protrusions respectively that, when the cutting device is in the extended position, are received within first and second recesses in the first and second grasping elements respectively.
Also provided is a surgical instrument including a shaft having a proximal end and a distal end, a handpiece disposed at the proximal end of the shaft, and a grasping device disposed at the distal end of the shaft having first and second jaw elements pivotally coupled to one another and pivotable relative to one another between opened position and a closed positions. The instrument further includes a cutting device having a first cutting element and a second cutting element pivotally coupled to the first cutting element. The cutting device is movable between a retracted position wherein it is positioned within the shaft and a extended position wherein it is disposed at the distal end of the shaft. When the cutting device is in the extended position, the first and second cutting elements are coupled to the first and second jaw elements respectively for movement therewith between open and closed positions, and at least one of said first and second cutting elements has a sharpened leading edge capable of dissecting tissue when the cutting device is moved from the retracted position to the extended position.
A method for surgically manipulating tissue is also provided including the steps of grasping a portion of tissue using a grasping device positioned at a distal end of a shaft of a surgical instrument, coagulating the grasped tissue by applying bipolar electrical energy to bipolar electrodes within the grasping device, and cutting the tissue by deploying a cutting device from a first position wherein it is retracted within the shaft of the surgical instrument, to a second position wherein it extends into the grasping device.
These and other features and advantages of the present invention will become apparent from the following more detailed description, when taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.